The following abbreviations are herewith defined, at least some of which are referred to within the following description.
3GPP Third Generation Partnership Project
ACK Positive-Acknowledgment
ANDSF Access Network Discovery and Selection Function
AP Access Point
APN Access Point Name
AS Access Stratum
BLER Block Error Ratio
BPSK Binary Phase Shift Keying
CAZAC Constant Amplitude Zero Auto Correction
CCA Clear Channel Assessment
CCE Control Channel Element
CP Cyclic Prefix
CQI Channel Quality Information
CSI Channel State Information
CRS Cell-Specific Reference Signal
CSS Common Search Space
DCI Downlink Control Information
DL Downlink
DMRS Demodulation Reference Signal
EDGE Enhanced Data Rates for Global Evolution
eNB Evolved Node B
EPDCCH Enhanced Physical Downlink Control Channel
E-RAB E-UTRAN Radio Access Bearer
ETSI European Telecommunications Standards Institute
E-UTRAN Evolved Universal Terrestrial Radio Access Network
FBE Frame Based Equipment
FDD Frequency Division Duplex
FDMA Frequency Division Multiple Access
FEC Forward Error Correction
GERAN GSM/EDGE Radio Access Network
GPRS General Packet Radio Service
GSM Global System for Mobile Communication
GTP GPRS Tunneling Protocol
HARQ Hybrid Automatic Repeat Request
H-PLMN Home Public Land Mobile Network
IoT Internet-of-Things
IP Internet Protocol
ISRP Inter-System Routing Policy
LAA Licensed Assisted Access
LBE Load Based Equipment
LBT Listen-Before-Talk
LTE Long Term Evolution
MCL Minimum Coupling Loss
MCS Modulation and Coding Scheme
MME Mobility Management Entity
MU-MIMO Multi-User, Multiple-Input, Multiple-Output
NACK or NAK Negative-Acknowledgment
NAS Non-Access Stratum
NBIFOM Network-Based IP Flow Mobility
NB-IoT NarrowBand Internet of Things
OFDM Orthogonal Frequency Division Multiplexing
PCell Primary Cell
PBCH Physical Broadcast Channel
PCID Physical Cell Identification (“ID”)
PCO Protocol Configuration Options
PCRF Policy and Charging Rules Function
PDCCH Physical Downlink Control Channel
PDCP Packet Data Convergence Protocol
PDN Packet Data Network
PDSCH Physical Downlink Shared Channel
PDU Protocol Data Unit
PGW Packet Data Network Gateway
PHICH Physical Hybrid ARQ Indicator Channel
PLMN Public Land Mobile Network
PRACH Physical Random Access Channel
PRB Physical Resource Block
PSS Primary Synchronization Signal
PUCCH Physical Uplink Control Channel
PUSCH Physical Uplink Shared Channel
QoS Quality of Service
QPSK Quadrature Phase Shift Keying
RAB Radio Access Bearer
RAN Radio Access Network
RAR Random Access Response
RE Resource Element
RRC Radio Resource Control
RS Reference Signal
RX Receive
SC-FDMA Single Carrier Frequency Division Multiple Access
SCell Secondary Cell
SCH Shared Channel
SGW Serving Gateway
SIB System Information Block
SINR Signal-to-Interference-Plus-Noise Ratio
SR Scheduling Request
SSS Secondary Synchronization Signal
TAU Tracking Area Update
TBS Transport Block Size
TCP Transmission Control Protocol
TDD Time-Division Duplex
TDM Time Division Multiplex
TED Tunnel Endpoint Identification (“ID”)
TX Transmit
UCI Uplink Control Information
UE User Entity/Equipment (Mobile Terminal)
UL Uplink
UMTS Universal Mobile Telecommunications System
V-PLMN Visited Public Land Mobile Network
WiMAX Worldwide Interoperability for Microwave Access
WLAN Wireless Local Area Network
In wireless communications networks, a frame structure for LTE FDD may be used. A radio frame of 10 milliseconds (“ms”) may include 10 subframes, each of which is 1 ms. Each subframe further may include two slots, each of which is 0.5 ms. Within each slot, a number of SC-FDMA symbols may be transmitted for UL transmission. The transmitted signal in each slot on an antenna port may be described by a resource grid comprising NRBULNscRB subcarriers and NsymbUL OFDM symbols, where NRBUL is number of RBs in the UL (which is dependent on the transmission bandwidth of a cell); NscRB is the number of subcarriers in each RB; and each subcarrier occupies a certain frequency of size Δf. The values of NscRB, Δf, and NsymbUL may depend on a cyclic prefix as shown in Table 1.
TABLE 1ConfigurationNscRBNsymbULNormal Cyclic PrefixΔf = 15 kHz127Extended Cyclic PrefixΔf = 15 kHz126
Two types of uplink reference signals may be supported in an LTE system: demodulation reference signals that are associated with transmission of PUSCH or PUCCH; and sounding reference signals that are not associated with transmission of PUSCH or PUCCH. The same set of base sequences may be used for demodulation and sounding reference signals. A reference signal sequence ru,v(α)(n) may be defined by a cyclic shift α of a base sequence ru,v(n) according to: ru,v(α)(n)=ejαn(n)ru,v(n), 0≤n<MscRS 
where MscRS=mNscRB is the length of the reference signal sequence and 1≤m≤NRBmax,UL. Multiple reference signal sequences may be defined from a single base sequence through different values of α.
Base sequences ru,v(n) may be divided into groups, where u∈{0, 1, . . . , 29} is the group number and v is the base sequence number within the group, such that each group contains one base sequence (v=0) of each length MscRS=mNscRB, 1≤m≤5 and two base sequences (v=0,1) of each length MscRS=mNscRB, 6≤m≤NRBmax,UL. The sequence group number u and the number v within the group may vary in time. The definition of the base sequence ru,v(0), . . . , ru,v(MscRS−1) may depend on the sequence length MscRS.
For MscRS=NscRB and MscRS=2NscRB, the base sequence is given by: ru,v=ejϕ(n)π/4, 0≤n≤MscRS−1
where the value of φ(n) for MscRS=NscRB is given by Table 2, as an example.
TABLE 2uφ(0), . . . , φ(11)0−113−3331131−33111333−11−3−31−33211−3−3−3−1−3−31−31−13−11111−1−3−31−33−14−131−11−1−3−11−11351−33−1−111−1−13−31. . . . . .
NarrowBand IoT (“NB-IoT”) specifies a radio access technology for cellular internet of things that addresses improved indoor coverage, support for massive number of low throughput devices, low delay sensitivity, ultra-low device cost, low device power consumption, and (optimized) network architecture.
NB-IoT may support the following different modes of operation: “Stand-alone operation” utilizing, for example, the spectrum currently being used by GERAN systems as a replacement of one or more GSM carriers; “Guard band operation” utilizing the unused resource blocks within an LTE carrier's guard-band; and “In-band operation” utilizing resource blocks within a normal LTE carrier.
An NB-IoT may support an RF and baseband bandwidth of 180 kHz, which is equivalent to one LTE Physical Resource Block (“PRB”). A unified DL design with 15 kHz subcarrier spacing for all three modes of operation may be used.
For UL both single tone and multi-tone operations may be supported. Specifically, for single tone transmissions, two numerologies (3.75 kHz, 15 kHz) may be configurable by the network. Moreover, for multi-tone transmissions, SC-FDMA with 15 kHz UL subcarrier spacing based transmission may be supported. This support structure follows the subframe structure of LTE PUSCH.
Three numerologies and resource unit configurations may be used. Specifically, a first structure using 12 subcarriers (15 kHz) with a 1 msec resource unit size; a second structure using 6 subcarriers with a 2 msec resource unit size; and a third structure using 3 subcarriers with a 4 msec resource unit size.
The slot format may be the same for NB-IoT in the multi-tone transmissions as it is in LTE. Accordingly, UL DMRS may use the same positions in NB-IoT as LTE. In certain NB-IoT UL multi-tone transmissions, the available DMRS symbols within the resource unit may be 2 (e.g., for a 12 subcarrier structure), 4 (e.g., for a 6 subcarrier structure), or 8 (e.g., for a 3 subcarrier structure). The current LTE system only has the 12 subcarrier configuration for UL DMRS defined. Accordingly, there is no definition for the 6 subcarrier configuration for UL DMRS and for the 3 subcarrier configuration for UL DMRS.